It is known that certain water-soluble phthalocyanine, naphthalocyanine, mixed cyanine, and metallocyanine compounds can be used as photobleaching and antimicrobial agents. Phthalocyanines and naphthalocyanines or their metal complexes can form "singlet oxygen" an oxidative species capable of reacting with stains to bleach them to a colorless and usually water-soluble state.
It has now been surprisingly found that certain porphyrin, metalloporphyrin, phthalocyanine, naphthalocyanine, mixed cyanine, and metallocyanine compounds can photochemically produce superoxide. Superoxide is typically formed via non-photochemical means from the disproportionation of alkali and alkaline earth metal superoxides.
Superoxide is a reactive oxygen species formed by the one electron reduction of oxygen, has a longer lifetime than singlet oxygen and is capable of decolorizing (bleaching) stains and killing bacteria. Throughout this application superoxide is represented as O.sub.2.sup.- based on common literature practice.
Surprisingly, it has been found that superoxide can be efficiently produced by photochemical means. Certain photosensitizing units which comprise a moiety capable of transfering an electron to the photochemically excited .pi. electron cloud of the photosensitizer unit, are capable of producing superoxide. Preferably the photosensitizers, preferably porphyrins, metalloporphyrins, cyanines, and metallocyanines, and have the electron transfering moiety covalently attached.
It is therefore an aspect of the present invention to provide novel materials that photochemically produce superoxide. These materials are photosensitizing units which have covalently attached a moiety capable of transfering an electron to the excited state of the aforementioned photosensitizer. The superoxide produced by these compounds is useful in that the superoxide molecules are capable of acting as bleaching materials or as antimicrobials.
It is a further aspect of the present invention to provide laundry detergent and hard surface cleaning compositions comprising the aforementioned superoxide generators.
In accordance with still another aspect of the present invention, a method for removing stains from fabric and for killing bacteria as well as preventing the re-propagation of said bacteria is herein provided. The method comprises contacting the fabrics or surface contaminated with bacteria with an aqueous medium comprising at least 0.001 ppm of the photochemical superoxide generators described herein below. These, and other objects, features, and advantages will be clear from the following detailed description and the appended claims.